PACS in Japan and the Nordic Countries. First Japan-Nordic PACS symposium.

The ingredients seem to exist for switching from film-based radiology to digital radiology utilizing the concept Picture Archiving and Communication System (PACS). Why has this not happened? What are the barriers limiting the diffusion of PACS into health care? This was the theme of the 1st Japan-Nordic Symposium in PACS, which was held in Tokyo, March 29-30, 1990. Over 40 radiologists and technical specialists in PACS participated. The topics discussed ranged from the present status of PACS in Japan and the Nordic Countries, to functional specifications and user requirements for PACS, to organizational and other changes brought about by PACS and to teleradiology as a solution for communication of images over wide distances. The symposium was quite successful and will be followed by a 2nd symposium in Finland in the summer of 1991.     

Experience of a small PACS in Tottori University Hospital.

Picture archiving and communications systems (PACS) are expected to become feasible as the way of total radiologic image management. As the first step towards computerized image management, we installed an experimental small PACS with a digital optical archive for magnetic resonance and digitized radiographic film images. During the first 10 months of operation, problems were caused by the frequent mechanical troubles on the acquisition devices, impractical schemes for transmission, and troublesome retrieval and display of images. Although some of them have been solved by the improvements of both hardware and software, the mechanical instability of the digitizer and the inadequate operating procedure of the workstation still remain. As to the characteristics of PACS, the capability of access to every achieved radiologic image is the great advantage for us because the image integration has been impossible in the form of radiographic films for the traditional image management system of our hospital. However, the complicated image display procedure with high overheads is far from ideal for radiologists. The efficiency of image display must be increased to the level of a conventional film viewing system. Furthermore, research is needed on the small PACS to get consensus for the acceptance of a more widely implemented system.     

Top-down design of a picture archiving and communications system (PACS) by means of simulation

The development of picture archiving and communications systems (PACS) for medical applications can be regarded as a challenging field in medical informatics. Since 1982, several projects have been started into this direction worldwide. The Dutch IMAGIS (Image Information System) project, started in 1984, is one of them. Within this project, a top-down design strategy is chosen, with the following first steps: (1) A thorough information analysis for a Radiology Department, in which both qualitative and quantitative aspects are included. Such an analysis can be used to estimate the workload on a future PACS system. (2) The construction of a flexible performance prediction tool, based on discrete even simulation. Such a tool can be used to predict the performance of a certain computer system configuration under a certain workload. Based on the information analysis, and using the performance prediction tool, a PACS system is drafted for the thorax section of the Diagnostic Radiology Department of the Leiden University Hospital. In this first design attempt, the assumption was made that current working procedures concerning images will be maintained as much as possible.     

JPEG compression for PACS.

In the medical field, especially in diagnostic radiology, there still remains controversy over how and whether or not to compress X-ray images for storage and transmission. The joint Photographic Expert Group (JPEG) standard which has recently been agreed upon is the very attractive technique to archive and to transport images in medical fields. This technique is based on 'lossy' compression of images, which can handle not only X-ray images but also full-colored images, and is suitable for introduction into picture archiving and communicating systems (PACS). The images can be handled after compression as quite small clusters of data. For example, a single 2000 x 2000 x 12 bits chest X-ray image which is an 8 Mbyte image compressed at a 10:1 ratio could retain virtually all the visible quality of the original version, and would take 100 s to transmit at 64 kbits/s using the Integrated Services Digital Network (ISDN, 800 kbytes compressed file, 8 kbytes/s transmission theoretically). An important factor in the design of this technique is that this format relies on no specific hardware or software if using JFIF (JPEG File interchange Format). Soon this algorithm will be able to run on any workstation or on any PC in the world. Highly compressed images may be unsuitable for diagnostic purposes. However, they may be sufficient for reference images which will be needed in clinical fields.     

Finnish PACS project.

A Finnish PACS project has been set up with the participation and financing of 13 university and central hospitals, the Medical Board of Finland, the Hospital League of Finland, the Post and Teleoffice of Finland and the Helsinki Telephone Company with the Medical Engineering Laboratory of the Technical Research Centre of Finland as the principal investigator. The project started in December 1988 and ended in December 1990. The project focused on the functional needs for PACS. The image production, archive sizes, network capacity and workstation requirements have been studied in a big university hospital. The results show that without compression the image archive size needs to be at least 10 TB. The network capacity requirement depends very much on the interactivity requirements. In normal situations less than 1 Mbit/s is needed, if the network is configured in an efficient way. In some cases, however, the speed requirement can be of the order of 100 Mbit/s. A proposal for a hospital-wide PACS network was made. Simple calculation rules to estimate the needed capacities were also developed.     

实现医学影象存档和传输系统中的若干关键技术

ＰＡＣＳ的重要性已被人们所认识,并且其技术在近１５ａ中得到了迅速发展。但是,实现ＰＡＣＳ仍然还有很多问题有待于解决。该文通过大量有关文献研究,指出并分析了实现ＰＡＣＳ过程中涉及到的关键技术,特别是对国际医学影象通信标准的内容进行了介绍;讨论了系统中有关影象存档和处理显示功能的软件设计方法;分析了常用的大容量影象数据存储方式,并给出了国内目前可行的解决方案。最后指出,为了跟上国际医学信息技术的发展潮     

PACS and the reporting system. Present status of PACS in the University of Tsukuba.

In the University of Tsukuba, PACS research is being carried out with a special emphasis on the reporting system. The radiological diagnostic system in Japan is not sufficiently developed and the number of diagnostic radiologists in Japan is not as large as in many European countries (M. Akisada, Present status of PACS activities in Japan. Med. Inform. 13 (1988) 289-293). With recognition of this fact, PACS research in Japan should also focus on the reporting system. Recently, the first PACS workstation was installed in the Department of Radiology of the University Hospital, but it has not yet been put to clinical use. Reports can be made on this workstation while viewing the properly provided digital images of MR and CT. As to the concepts of the reporting system, there are three important points. The first one is the double check system to maintain the standard quality of diagnostic performance. This system is expected to provide proper training and education to students and young doctors (S.E. Selzer, S.J. Hessel, P.G. Herman et al., Resident film interpretations and staff review. Am. J. Radiol. 137 (1981) 129-133). The second one is to develop a transcriber workstation, through which reports are easily handled as routine work. The last point is to provide a well-organized diagnostic coding system. For this purpose, a modified IRD (Index for Radiological Diagnosis, by the American College of Radiology) is assumed to be one of the best choices.     

The goal of PACS in Nagoya University Hospital.

In Nagoya University Hospital, a Radiology Intelligent Information System (RIIS) is under construction which will be linked with the Hospital Intelligent Information System (HIIS). RIIS is composed of the radiation oncology information system and the diagnostic radiology information system which is named Imaging Diagnosis Intelligent Information System (IDIIS). IDIIS consists of three parts: (a) the Imaging Diagnosis Management System (IDMS); (b) the Picture Archiving and Communication System (PACS); (c) the Report Generation Support System for Imaging Diagnosis (RGSS-ID). Artificial intelligence methodology is applied to RGSS-ID and IDMS which includes the ordering and scheduling system of diagnostic imaging. IDIIS has an important role to improve the quality of patient care and medical education as well as image management and is an essential component for the implementation of HIIS.     

面向Internet的组件式PACS系统设计

总结了近几年我国ＰＡＣＳ的发展概况,分析了ＰＡＣＳ的发展方向,认为ＰＡＣＳ的发展应遵循模块化设计、部门级优化、阶段化实现的方针,针对大型ＰＡＣＳ的发展提出基于Ｃ（ＯＭ技术的和ＤＮＡ结构的“组件式ＰＡＣＳ系统”的概念,系统重视各部门工作的协调统一,面向Ｉｎｔｅｒｎｅｔ,较好解决了系统界定、部门优化、远程通信、柔化实现等问题。     

PACS设计与实现中的几个关键问题

医学图像归档及通信系统（PACS）的设计与实现是医学图像处理领域的研究热点,同时对医院构建放射学信息系统、医院信息系统有着重要意义。结合开发图像归档服务器的经验,分析和探讨了PACS设计和实现中的几个关键问题,比如PACS的功能选择、PACS底层通信协议的选择、数据库的管理、图像存储媒体的选择、图像诊断工作站的选择、支持远程医疗的WEB数据发布策略等等。最后,阐述了一个新构建的小型PACS的机构和主要技术。     

PACS系统在医院的应用

PACS已成为医院信息系统中的一个重要组成部分。本文从医院实际情况出发,分析了PACS系统的工作流程及各模块的功能,以及实施后的带来的好处。     

Planning for PACS at Osaka University Hospital.

We have a plan to adopt PACS as a medical image information system in the new hospital. In order to construct PACS suitable for our hospital, a preliminary survey was carried out to determine how PACS should be introduced and what are the physicians requirements for a new medical image system. The most important requirement of the physicians was a good quality workstation. Our plan of a new medical image information system is as follows. A primary database will be constructed according to each of modalities in the Department of Radiology. In the Department of Medical Information Science, we will make a secondary database according to the patient. Although it may be difficult for us to obtain a sufficient budget digitalizing all medical images by our move to the new hospital, our goal is to establish total PACS throughout the new hospital in 1995.     

Status of PACS and technology assessment in Japan

The situation of PACS installations in Japan from 1987 to 1999 has been investigated. By 1999, 751 PACS units have been installed. Of these, 613 are small-size PACS with less than four image display terminals, 96 are medium-size with 5-14 terminals and 42 are large-size with 15 up to 300 terminals. The 42 hospitals with large sized PACS have been retrospectively investigated from 1984 for PACS experiments and from 1989 for PACS operation. Most of these 42 hospitals have increased the number of PACS terminals by installing additional PACS units instead of reinforcing the existing single PACS. Some (23%) PACS installations have obviously not been successful because of low image transfer speed and inadequate image quality. The use of DICOMM interfaces has increased the number of modalities connected to PACS and influenced the spread of PACS installations in Japan. The status of HIS and RIS coupling to PACS and the use of PACS in primary diagnosis or in image referral are discussed. Assessment of PACS is now in a very early stage. Baseline studies of HIS/RIS/PACS effectiveness have been carried out to assess quantitatively the PACS merit. Radiologists' answers to the questionnaire on PACS usage do not fully support the finding that the number of PACS installations is growing in Japan.     

Do the benefits outweigh the costs of PACS? The results of an International Workshop on Technology Assessment of PACS.

On May 26-27, 1991, an International Workshop on the Technology Assessment of PACS was held at Enkhuizen, The Netherlands. During this workshop 35 experts in the field, from 13 different countries, discussed amongst others the required functionality of PACS, diagnostic aspects and the quality of care and organizational aspects. The key question was whether, when and how PACS is feasible, both from a financial and a clinical point of view. Data which were collected with the aid of the software tool CAPACITY formed the starting point of this meeting. This paper gives an outline of the discussions during this workshop. The main conclusion is that more clinical research is needed, to get a better insight into the costs and the clinical benefits of PACS. Because of the high costs of the PACS technology, international cooperation in this field is requested. It is recommended that the CAPACITY project, which is set up to stimulate the international dialogue and data exchange on PACS, is continued.     

PACS and patient data management systems.

It is important for a PACS to have access to the patient data, as well as to the images themselves, for the purpose of sophisticated image archiving, retrieving, viewing and interpretation. There are many kinds of patient data concerning image examinations (i.e., patient name, ID, age, examination date and time, examined regions, methods, findings on images, diagnoses or diagnostic impressions, etc.). Some of them are acquired from image examination apparatus, some are supplied by diagnostic radiologists, while some need be retrieved from the radiology and hospital information systems. To facilitate this data exchange, a PACS-RIS-HIS coupling is required. The author has constructed at Tokyo University Hospital a small PACS called TRACS, which adopts one of the possible PACS-RIS-HIS coupling configurations.     

PACS技术及其应用

介绍了ＰＡＣＳ在开发和的一些关键技术,并结合实际应用情况对该系统作出了评价。     

Present status and performance of PACS at Kyoto University Hospital.

A pilot PACS project, named KIDS, has been running in Kyoto University Hospital. The purpose of the system is to establish a small PACS that includes all digital imaging modalities and to evaluate it. The project has been continued from the first phase (KIDS-1) to the second phase (KIDS-2). In the first phase, a small-scale PACS was developed. In the second phase, the expansion of coverage of modalities and completion of the image database was intended. At present, the database contains image data of 16264 patients amounting to 150 Gbytes. Simulation of the retrieval process to the database shows that 154.3 s per patient is required for retrieving his/her entire image data. This calculated value is close to the actual time.     

PACS与HIS/RIS集成方法的研究*

介绍了PACS和HIS/RIS所管理的信息对象及遵循的标准,详细阐述了PACS与HIS/RIS之间的集成方法,并结合实例说明了如何用DICOM标准实现它们之间的无缝连接。最后讨论了医院信息系统的发展趋势。     

分布式对象技术与医学工业标准相结合的PACS体系结构研究

10多年来，PACS经历了两代的发展过程，今天正处于第三代发展中，其体系结构作为研究的重要内容之一也随之逐步演变，回顾了第一、第二代PACS体系结构的特点，并分析了当前最新的基于医学工业标准的PACS体系结构，指出了其不足之处，而后，通过对分布式对象技术以及三级客户/服务器结构的特点进行分析。指出分布式对象技术可以解决PACS体系结构存在的问题，研究了分布式对象技术与医学工业标准相结合的PACS体系结构。并给出了设计方案。     

Automating object-oriented integration and visualization of multidisciplinary biomedical data in radiology workflow: Compartmental PACS model

This paper is aimed to present a novel compartmental PACS model for the automatic object-oriented integration and visualization of heterogeneous data for the multidisciplinary biomedical studies in the midst of the imaging services in radiology department. The generic PACS is conceptually partitioned into two compartments: service and integration. The service compartment supports the routine imaging service by connecting the imaging modalities to the web client workstations through a single fault-tolerant hardware. The integration compartment is synthesized by open source and open standard software tools to perform the long-term archiving of imaging cases and to integrate the images with the related data from other clinical disciplines. The prototype of the compartmental PACS model has been successfully implemented in the Department of Health Technology and Informatics (HTI) at the Hong Kong Polytechnic University (PolyU). Multi-disciplinary study on a cardiovascular case is considered as an example in this paper to demonstrate the seamless integration and web-based visualization of heterogeneous data from radiology, ophthalmology, cardiology and hematology. The implementation of the compartmental PACS model demonstrates a deliberative system design for allocating mission-critical components at the clinical frontline of imaging services and long-term archiving components at the backend. The integrative feature of object-oriented long-term archive addresses the comprehensive needs of patient-centered multidisciplinary biomedical studies.